Automated real-time drilling fluid density

ABSTRACT

Methods, systems, and computer-readable medium to perform operations including: determining, in real-time, values of drilling parameters of a drilling system drilling a wellbore; calculating, based on the values of the drilling parameters, a cuttings concentration in an annulus of the wellbore (CCA); calculating, based on the calculated CCA and a mud weight (MW) of a drilling fluid, an effective mud weight (MWeff) of the drilling fluid; and controlling, based on the effective mud weight, a component of the drilling system to adjust at least one of the drilling parameters.

The present disclosure relates to oil field exploration and, inparticular, to methods and systems for calculating drilling fluiddensity.

BACKGROUND

In wellbore drilling, a drilling system causes a drill bit to rotatewhen in contact with a formation. The rotation of the drill bit breaksand fractures the formation to form the wellbore. When drilling thewellbore, the drilling system circulates a drilling fluid (also referredto as drilling mud or mud) to the drill bit where the drilling fluidexits through drill bit nozzles to the bottom of the wellbore. Thedrilling fluid serves many purposes including, but not limited to,cooling the drill bit, supplying hydrostatic pressure upon the formationto prevent fluids from flowing into the wellbore, and carrying formationcuttings from the wellbore to the surface.

SUMMARY

The present disclosure describes methods and systems for calculating adrilling fluid density and using the calculation to improve drillingoperations. The methods and systems utilize real-time input parametersto calculate the drilling fluid density. In an embodiment, the drillingfluid density is calculated based on a cuttings concentration in theannulus (CCA), which is calculated from real-time values of drillingparameters. This drilling fluid density accounts for real-time cuttingsweight and drilling fluid weight. This calculation of drilling fluiddensity is then used to adjust drilling parameters to improve drillingoperations.

Aspects of the subject matter described in this specification may beembodied in methods that include the actions of: determining, inreal-time, values of drilling parameters of a drilling system drilling awellbore; calculating, based on the values of the drilling parameters, acuttings concentration in an annulus of the wellbore (CCA); calculating,based on the calculated CCA and a mud weight (MW) of a drilling fluid,an effective mud weight (MW_(eff)) of the drilling fluid; andcontrolling, based on the effective mud weight, a component of thedrilling system to adjust at least one of the drilling parameters.

The previously-described implementation is implementable using acomputer-implemented method; a non-transitory, computer-readable mediumstoring computer-readable instructions to perform thecomputer-implemented method; and a computer system comprising a computermemory interoperably coupled with a hardware processor configured toperform the computer-implemented method/the instructions stored on thenon-transitory, computer-readable medium. These and other embodimentsmay each optionally include one or more of the following features.

In a first aspect, the effective mud weight is calculated using theequation: (MW_(eff))=(MW*CCA)+MW. In a second aspect, the drillingparameters comprise: a rate of penetration (ROP) of a drilling tool ofthe drilling system, a hole size of the wellbore, and a flow rate (GPM)of the drilling fluid. In a third aspect, CCA is calculated using theequation

${{CCA} = \frac{{ROP}*{hole}{size}^{2}}{1471*{GPM}*TR}},$wherein TR is a cuttings transport ratio. In a fourth aspect,controlling, based on the effective mud weight, a component of thedrilling system to adjust at least one of the drilling parameterscomprises: determining, based on the effective mud weight, a rate ofpenetration for a drilling tool of the drilling system, and controllingthe drilling tool such that the rate of penetration of the drilling toolis less than or equal to the determined rate of penetration. In a fifthaspect, determining the rate of penetration for the drilling tool isfurther based on a pore pressure limit and a fracture pressure limit. Ina sixth aspect, the rate of penetration is calculated using theequation:

${ROP}{{= \frac{810*\left( {{MW}_{eff} - {MW}} \right)*GPM}{\left( {{MW}*{OH}^{2}} \right)}},}$where ROP is the rate of penetration, OH is an open hole size of thewellbore, and GPM is a flow rate of the drilling fluid.

DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of an example drilling system, according tosome implementations of the present disclosure.

FIGS. 2A, 2B, 3A, 3B, 4A, and 4B are graphs that compare effective mudweight calculated using commercial methods and effective mud weightcalculated using the disclosed methods at different wellbore depths,according to some implementations.

FIG. 5 is a flowchart of an example method for calculating drillingfluid density in real-time, according to some implementations of thepresent disclosure.

FIG. 6 is a block diagram of an example computer system used to providecomputational functionalities associated with described algorithms,methods, functions, processes, flows, and procedures as described in thepresent disclosure, according to some implementations of the presentdisclosure.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

The following detailed description describes methods and systems forcalculating drilling fluid density and using the calculation to improvedrilling operations. Various modifications, alterations, andpermutations of the disclosed implementations can be made and will bereadily apparent to those of ordinary skill in the art. Additionally,the general principles defined may be applied to other implementationsand applications without departing from the scope of the disclosure. Insome instances, details unnecessary to obtain an understanding of thedescribed subject matter may be omitted so as to not obscure one or moredescribed implementations with unnecessary detail and since such detailsare within the skill of one of ordinary skill in the art. The presentdisclosure is not intended to be limited to the described or illustratedimplementations but to be accorded the widest scope consistent with thedescribed principles and features.

When using a drilling fluid in a drilling operation, the drilling fluidproperty that determines the drilling fluid performance is the drillingfluid density (also referred to as mud weight or mud density). Thedrilling fluid density directly affects many properties of the wellbore,such as wellbore stability, fluid circulation in the wellbore, andformation damage. Accordingly, the drilling fluid density can be used toderive values for wellbore properties. However, during drilling, variousfactors, such as cuttings from the formation, affect the drilling fueldensity. Current drilling fluid density values used in practice are notdynamic values that account for these factors. As a result, models thatrely on these drilling fluid densities are inaccurate.

Disclosed are methods and systems for calculating drilling fluid densityin real-time during a drilling operation. For example, the term“real-time” can correspond to events that occur within a specifiedperiod of time, such as within one minute, within one second, or withinmilliseconds. The drilling fluid density calculated in real-time isreferred to as an effective drilling fluid density. In animplementation, the calculation is based on a cuttings concentration inthe annulus (CCA), which is determined using real-time values ofdrilling parameters. Because the calculation is based on the CCA, theeffective drilling fluid density accounts for both the weight ofcuttings and the static drilling fluid density. Furthermore, because theeffective drilling fluid density is a real-time value, monitoring theeffective density allows a drilling system to make decisions whether toadjust corresponding drilling parameters to improve the drillingoperation.

FIG. 1 is a block diagram of an example drilling system 100 for drillinga wellbore, according to some implementations. The drilling system 100includes rotating equipment 102, circulating system 104, logging andmeasuring equipment 106, and controller 120. The rotating equipment 102,which is responsible for rotary drilling, includes drill string 108,drill bit 110, and drill pipe 112. The circulating system 104, which isresponsible for the circulation of drilling fluid, includes mud pump114, mud pit(s) 116, and drill bit nozzle 118. The logging and measuringequipment 106 includes sensors, tools, and devices that are configuredfor measurement while drilling (MWD), logging while drilling (LWD), orboth. The controller 120 is a computer system (for example, computersystem 600 shown in FIG. 6) that is configured to control one or morecomponents of the drilling system 100.

To drill the wellbore, the drilling system 100 lowers the drill bit 110,which is attached to the drill string 108, into a well until the drillbit 110 makes contact with a formation. Once in contact, the drill bit110 is rotated to break and fracture the formation, thereby forming thewellbore. As the rotating equipment 102 is drilling the wellbore, themud pump 114 withdraws drilling fluid from the mud pit(s) 116 and pumpsthe drilling fluid down the drill string 108 through the drill bitnozzles 118 that are located on the drill bit 110. The drilling fluidflows to the bottom of the wellbore and upward to the surface via anannulus formed between the drilling string 108 and the walls of thewellbore. When flowing to the surface, the drilling fluid carriesportions of the formation, called cuttings, that are fractured by therotating drill bit 110. At the surface, the circulating system 104filters the cuttings from the drilling fluid and then pumps the drillingfluid back down to the bottom the wellbore.

In an embodiment, during a drilling operation, the drilling system 100determines, in real-time, the effective drilling fluid density. In animplementation, the drilling fluid density is calculated based on acuttings concentration in the annulus (CCA), which is calculated usingreal-time values of drilling parameters. The real-time values ofdrilling parameters are obtained from logging and measuring tools 106,surface logs, or daily drilling reports. The drilling parameters thatare used to calculate the CCA include the rate of penetration (ROP) ofthe drill bit 110, a hole size of the wellbore, and a flow rate of themud pump 114. In an example, the CCA is calculated using equation (1):

$\begin{matrix}{{CCA} = {\frac{{ROP}*{Hole}{Size}^{2}}{1471*GPM*TR}.}} & (1)\end{matrix}$In equation (1), “Hole Size” is the diameter of the wellbore (in feet),ROP is a rate of penetration (drilling rate, in feet/hour) of a drillingtool (for example, drill bit 110), GPM is the flow rate (in gallon perminutes) of the drilling fluid, and TR represents a transport ratio ofthe cuttings to the surface. In some examples, TR is approximated as aconstant with a value of 0.55.

In an example, the effective drilling fluid density is calculated usingequation (2):(MW _(eff))=(MW*CCA)+MW.  (2)In equation (2), MW_(eff) is the effective drilling fluid density (inpounds per gallon (lb/gal)) and MW is the static drilling fluid density(that is, the drilling fluid density without any cuttings). As shown byequation (2), the effective drilling fluid density accounts for thestatic drilling fluid density and the cuttings concentration.

Once the effective drilling fluid density is calculated, the drillingsystem 100 can use the density to determine information about thedrilling operation. As an example, the drilling system 100 uses theeffective drilling fluid density to determine a stability of theformation. In particular, the effective drilling fluid density isindicative of the hydrostatic pressure on the formation, and therefore,the drilling system 100 can use the effective drilling fluid density toderive the stability of the formation. As another example, the effectivedrilling fluid density is indicative of an extent of cuttingsaccumulation in the annulus. As yet another example, the effectivedrilling fluid density is indicative of an amount of fluid of dilutionin circulation.

From the derived information about the drilling operation, the drillingsystem 100 can determine to make one or more adjustments to theoperation, perhaps to meet changing downhole conditions. The adjustmentsmay be to surface properties, mechanical parameters (for example, ROP,flow rate, pipe-rotation speed, and tripping speed), or both. Inresponse to making the determination to make one or more adjustments,the drilling system 100 adjusts the operating parameters of one or morecomponents of the drilling system 100 to adjust the surface properties,the mechanical parameters, or both.

In an example, based on the effective drilling fluid density, thedrilling system 100 determines a maximum rate of penetration for thedrill bit 110. More specifically, the effective drilling fluid density,a pore pressure limit of the formation, and a fracture pressure limit ofthe formation are used to calculate the stability of the formation.Then, based on the calculated stability, the maximum rate of penetrationis calculated. Additionally, the drilling system 100 can control therate of penetration, perhaps to be less than the calculated maximumrate. Controlling the rate of penetration based on the effectivedrilling fluid density allows the drilling system 100 to: (i) avoidfracturing the formation while drilling, (ii) ensure smooth drillingwith generated drilling cuttings, and (iii) avoid or mitigate stuck pipeincidents.

In an example, the rate of penetration may be calculated using theeffective drilling fluid density using equation (3):

$\begin{matrix}{{ROP}{= \frac{810*\left( {{MW}_{eff} - {MW}} \right)*GPM}{\left( {{MW}*{OH}^{2}} \right)}}} & (3)\end{matrix}$In equation (3), MW_(eff) is the effective mud weight in pound-force percubic foot (PCF), MW is the designed mud weight in PCF, GPM is the flowrate of mud pump gallon per minutes, and OH is open-hole size in inches(in).

In another example, based on the effective drilling fluid density, thedrilling system 100 adjusts the drilling fluid density. In oneimplementation, the drilling system 100 adjusts the drilling fluiddensity by controlling the mud pump 114 to increase or decrease thevolume of drilling fluid pumped into the borehole. Increasing the volumeof drilling fluid decreases the drilling fluid density by dilution anddecreasing the volume of drilling fluid increases the drilling fluiddensity. In another implementation, the drilling system 100 increasesthe drilling fluid density by adding a weighing agent to the drillingfluid.

FIGS. 2A, 2B, 3A, 3B, 4A, and 4B are graphs that compare effective mudweight calculated using commercial methods and effective mud weightcalculated using the disclosed methods at different wellbore depths,according to some implementations. In particular, the graphs compare theeffective mud weight calculated using Baralogix® (commercially availablefrom Halliburton) and the effective mud weight calculated using thedisclosed methods. FIGS. 2A, 3A, and 4A illustrate graphs of theeffective mud weight, at different depths, calculated using Baralogix®.FIGS. 2B, 3B, and 4B illustrate graphs of the effective mud weight, atdifferent depths, calculated using the disclosed methods. As shown bythese figures, the mud weight calculated using the disclosed methods issimilar to the mud weight calculated using Baralogix®.

FIG. 5 is a flowchart of an example method 500 for calculating effectivedrilling fluid density in real-time, according to some implementations.For clarity of presentation, the description that follows generallydescribes method 500 in the context of the other figures in thisdescription. However, it will be understood that method 500 can beperformed, for example, by any suitable system, environment, software,and hardware, or a combination of systems, environments, software, andhardware, as appropriate. In some implementations, various steps ofmethod 600 can be run in parallel, in combination, in loops, or in anyorder.

Method 500 begins at step 502, which involves determining, in real-time,values of drilling parameters of a drilling system drilling a wellbore.The term real-time can correspond to events that occur within aspecified period of time, such as within one minute, within one second,or within milliseconds. In some implementations, some of thesevariables, such as ROP, hole size, GPM, TR, can be automaticallyextracted from a received survey log. In some implementations, some ofthese variables, such as density of the drilling fluid, annularvelocity, and rheology factors, can be automatically extracted from areceived rheology log. In other implementations, the drilling parametersare determined from one or more additional sources such as measuringwhile drilling (MWD) tools, logging while drilling (LWD) tools, anddaily drilling reports (also referred to as “morning reports”).

At step 504, method 500 includes calculating, based on the values of thedrilling parameters, a cuttings concentration in an annulus of thewellbore (CCA). In an implementation, the drilling parameters that areused to calculate the CCA include a rate of penetration (ROP) of adrilling tool, a cuttings transport ratio (TR), a hole size of thewellbore, and a mud pump flow rate (GPM). In an example, the CCA iscalculated using the equation:

${CCA} = {\frac{{ROP}*{Hole}{Size}^{2}}{1461*{GP}M*TR}.}$In some examples, TR is estimated as 0.55.

At step 506, method 500 includes calculating, based on the calculatedCCA and a mud weight (MW) of a drilling fluid, an effective mud weight(MW_(eff)) of the drilling fluid. In an example, the effective drillingfluid density is calculated using the equation: MW_(eff)=(MW*CCA)+MW.

At 508, method 500 involves controlling, based on the effective mudweight, a component of the drilling system to adjust at least one of thedrilling parameters. In an example, based on the effective drillingfluid density, the drilling system determines a maximum rate ofpenetration. The rate of penetration may be calculated using theeffective drilling fluid density using the equation

${ROP} = {\frac{810*\left( {{MW}_{eff} - {MW}} \right)*GPM}{\left( {{MW}*{OH}^{2}} \right)}.}$In another example, based on the effective drilling fluid density, thedrilling system adjusts the drilling fluid density.

The example method 500 shown in FIG. 5 can be modified or reconfiguredto include additional, fewer, or different steps (not shown in FIG. 5),which can be performed in the order shown or in a different order.

FIG. 6 is a block diagram of an example computer system 600 used toprovide computational functionalities associated with describedalgorithms, methods, functions, processes, flows, and proceduresdescribed in the present disclosure, according to some implementationsof the present disclosure. The illustrated computer 602 is intended toencompass any computing device such as a server, a desktop computer, alaptop/notebook computer, a wireless data port, a smart phone, apersonal data assistant (PDA), a tablet computing device, or one or moreprocessors within these devices, including physical instances, virtualinstances, or both. The computer 602 can include input devices such askeypads, keyboards, and touch screens that can accept user information.In addition, the computer 602 can include output devices that can conveyinformation associated with the operation of the computer 602. Theinformation can include digital data, visual data, audio information, ora combination of information. The information can be presented in agraphical user interface (UI) (or GUI).

The computer 602 can serve in a role as a client, a network component, aserver, a database, a persistency, or components of a computer systemfor performing the subject matter described in the present disclosure.The illustrated computer 602 is communicably coupled with a network 630.In some implementations, one or more components of the computer 602 canbe configured to operate within different environments, includingcloud-computing-based environments, local environments, globalenvironments, and combinations of environments.

At a high level, the computer 602 is an electronic computing deviceoperable to receive, transmit, process, store, and manage data andinformation associated with the described subject matter. According tosome implementations, the computer 602 can also include, or becommunicably coupled with, an application server, an email server, a webserver, a caching server, a streaming data server, or a combination ofservers.

The computer 602 can receive requests over network 630 from a clientapplication (for example, executing on another computer 602). Thecomputer 602 can respond to the received requests by processing thereceived requests using software applications. Requests can also be sentto the computer 602 from internal users (for example, from a commandconsole), external (or third) parties, automated applications, entities,individuals, systems, and computers.

Each of the components of the computer 602 can communicate using asystem bus 603. In some implementations, any or all of the components ofthe computer 602, including hardware or software components, caninterface with each other or the interface 604 (or a combination ofboth), over the system bus 603. Interfaces can use an applicationprogramming interface (API) 612, a service layer 613, or a combinationof the API 612 and service layer 613. The API 612 can includespecifications for routines, data structures, and object classes. TheAPI 612 can be either computer-language independent or dependent. TheAPI 612 can refer to a complete interface, a single function, or a setof APIs.

The service layer 613 can provide software services to the computer 602and other components (whether illustrated or not) that are communicablycoupled to the computer 602. The functionality of the computer 602 canbe accessible for all service consumers using this service layer.Software services, such as those provided by the service layer 613, canprovide reusable, defined functionalities through a defined interface.For example, the interface can be software written in JAVA, C++, or alanguage providing data in extensible markup language (XML) format.While illustrated as an integrated component of the computer 602, inalternative implementations, the API 612 or the service layer 613 can bestand-alone components in relation to other components of the computer602 and other components communicably coupled to the computer 602.Moreover, any or all parts of the API 612 or the service layer 613 canbe implemented as child or sub-modules of another software module,enterprise application, or hardware module without departing from thescope of the present disclosure.

The computer 602 includes an interface 604. Although illustrated as asingle interface 604 in FIG. 6, two or more interfaces 604 can be usedaccording to particular needs, desires, or particular implementations ofthe computer 602 and the described functionality. The interface 604 canbe used by the computer 602 for communicating with other systems thatare connected to the network 630 (whether illustrated or not) in adistributed environment. Generally, the interface 604 can include, or beimplemented using, logic encoded in software or hardware (or acombination of software and hardware) operable to communicate with thenetwork 630. More specifically, the interface 604 can include softwaresupporting one or more communication protocols associated withcommunications. As such, the network 630 or the interface's hardware canbe operable to communicate physical signals within and outside of theillustrated computer 602.

The computer 602 includes a processor 605. Although illustrated as asingle processor 605 in FIG. 6, two or more processors 605 can be usedaccording to particular needs, desires, or particular implementations ofthe computer 602 and the described functionality. Generally, theprocessor 605 can execute instructions and can manipulate data toperform the operations of the computer 602, including operations usingalgorithms, methods, functions, processes, flows, and procedures asdescribed in the present disclosure.

The computer 602 also includes a database 606 that can hold data for thecomputer 602 and other components connected to the network 630 (whetherillustrated or not). For example, database 606 can be an in-memory,conventional, or a database storing data consistent with the presentdisclosure. In some implementations, database 606 can be a combinationof two or more different database types (for example, hybrid in-memoryand conventional databases) according to particular needs, desires, orparticular implementations of the computer 602 and the describedfunctionality. Although illustrated as a single database 606 in FIG. 6,two or more databases (of the same, different, or combination of types)can be used according to particular needs, desires, or particularimplementations of the computer 602 and the described functionality.While database 606 is illustrated as an internal component of thecomputer 602, in alternative implementations, database 606 can beexternal to the computer 602.

The computer 602 also includes a memory 607 that can hold data for thecomputer 602 or a combination of components connected to the network 630(whether illustrated or not). Memory 607 can store any data consistentwith the present disclosure. In some implementations, memory 607 can bea combination of two or more different types of memory (for example, acombination of semiconductor and magnetic storage) according toparticular needs, desires, or particular implementations of the computer602 and the described functionality. Although illustrated as a singlememory 607 in FIG. 6, two or more memories 607 (of the same, different,or combination of types) can be used according to particular needs,desires, or particular implementations of the computer 602 and thedescribed functionality. While memory 607 is illustrated as an internalcomponent of the computer 602, in alternative implementations, memory607 can be external to the computer 602.

The application 608 can be an algorithmic software engine providingfunctionality according to particular needs, desires, or particularimplementations of the computer 602 and the described functionality. Forexample, application 608 can serve as one or more components, modules,or applications. Further, although illustrated as a single application608, the application 608 can be implemented as multiple applications 608on the computer 602. In addition, although illustrated as internal tothe computer 602, in alternative implementations, the application 608can be external to the computer 602.

The computer 602 can also include a power supply 614. The power supply614 can include a rechargeable or non-rechargeable battery that can beconfigured to be either user- or non-user-replaceable. In someimplementations, the power supply 614 can include power-conversion andmanagement circuits, including recharging, standby, and power managementfunctionalities. In some implementations, the power-supply 614 caninclude a power plug to allow the computer 602 to be plugged into a wallsocket or a power source to, for example, power the computer 602 orrecharge a rechargeable battery.

There can be any number of computers 602 associated with, or externalto, a computer system containing computer 602, with each computer 602communicating over network 630. Further, the terms “client,” “user,” andother appropriate terminology can be used interchangeably, asappropriate, without departing from the scope of the present disclosure.Moreover, the present disclosure contemplates that many users can useone computer 602 and one user can use multiple computers 602.

Described implementations of the subject matter can include one or morefeatures, alone or in combination.

For example, in a first implementation, a computer-implemented method,comprising: determining, in real-time, values of drilling parameters ofa drilling system drilling a wellbore; calculating, based on the valuesof the drilling parameters, a cuttings concentration in an annulus ofthe wellbore (CCA); calculating, based on the calculated CCA and a mudweight (MW) of a drilling fluid, an effective mud weight (MW_(eff)) ofthe drilling fluid; and controlling, based on the effective mud weight,a component of the drilling system to adjust at least one of thedrilling parameters. The foregoing and other described implementationscan each, optionally, include one or more of the following features:

A first feature, combinable with any of the following features, wherethe effective mud weight is calculated using the equation:(MW_(eff))=(MW*CCA)+MW.

A second feature, combinable with any of the previous or followingfeatures, where the drilling parameters comprise: a rate of penetration(ROP) of a drilling tool of the drilling system, a hole size of thewellbore, and a flow rate (GPM) of the drilling fluid.

A third feature, combinable with any of the previous or followingfeatures, where the CCA is calculated using the equation:

${{CCA} = \frac{{ROP}*{hole}{size}^{2}}{1471*{GPM}*TR}},$wherein TR is a cuttings transport ratio.

A fourth feature, combinable with any of the previous or followingfeatures, where controlling, based on the effective mud weight, acomponent of the drilling system to adjust at least one of the drillingparameters includes: determining, based on the effective mud weight, arate of penetration for a drilling tool of the drilling system; andcontrolling the drilling tool such that the rate of penetration of thedrilling tool is less than or equal to the determined rate ofpenetration.

A fifth feature, combinable with any of the previous or followingfeatures, where determining the rate of penetration for the drillingtool is further based on a pore pressure limit and a fracture pressurelimit.

A sixth feature, combinable with any of the previous or followingfeatures, where the rate of penetration is calculated using theequation:

${{ROP} = \frac{810*\left( {{MW}_{eff} - {MW}} \right)*GPM}{\left( {{MW}*{OH}^{2}} \right)}},$where ROP is the rate of penetration, OH is an open hole size of thewellbore, and GPM is a flow rate of the drilling fluid.

In a second implementation, a non-transitory, computer-readable mediumstoring one or more instructions executable by a computer system toperform operations comprising any of the previous steps.

In a third implementation, a computer-implemented system, comprising oneor more processors and a non-transitory computer-readable storage mediumcoupled to the one or more processors and storing programminginstructions for execution by the one or more processors, theprogramming instructions instructing the one or more processors toperform operations comprising any of the previous steps.

Implementations of the subject matter and the functional operationsdescribed in this specification can be implemented in digital electroniccircuitry, in tangibly embodied computer software or firmware, incomputer hardware, including the structures disclosed in thisspecification and their structural equivalents, or in combinations ofone or more of them. Software implementations of the described subjectmatter can be implemented as one or more computer programs. Eachcomputer program can include one or more modules of computer programinstructions encoded on a tangible, non-transitory, computer-readablecomputer-storage medium for execution by, or to control the operationof, data processing apparatus. Alternatively, or additionally, theprogram instructions can be encoded in/on an artificially generatedpropagated signal. The example, the signal can be a machine-generatedelectrical, optical, or electromagnetic signal that is generated toencode information for transmission to suitable receiver apparatus forexecution by a data processing apparatus. The computer-storage mediumcan be a machine-readable storage device, a machine-readable storagesubstrate, a random or serial access memory device, or a combination ofcomputer-storage mediums.

The terms “data processing apparatus,” “computer,” and “electroniccomputer device” (or equivalent as understood by one of ordinary skillin the art) refer to data processing hardware. For example, a dataprocessing apparatus can encompass all kinds of apparatus, devices, andmachines for processing data, including by way of example, aprogrammable processor, a computer, or multiple processors or computers.The apparatus can also include special purpose logic circuitryincluding, for example, a central processing unit (CPU), a fieldprogrammable gate array (FPGA), or an application-specific integratedcircuit (ASIC). In some implementations, the data processing apparatusor special purpose logic circuitry (or a combination of the dataprocessing apparatus or special purpose logic circuitry) can behardware- or software-based (or a combination of both hardware- andsoftware-based). The apparatus can optionally include code that createsan execution environment for computer programs, for example, code thatconstitutes processor firmware, a protocol stack, a database managementsystem, an operating system, or a combination of execution environments.The present disclosure contemplates the use of data processingapparatuses with or without conventional operating systems, for example,LINUX, UNIX, WINDOWS, MAC OS, ANDROID, or IOS.

A computer program, which can also be referred to or described as aprogram, software, a software application, a module, a software module,a script, or code, can be written in any form of programming language.Programming languages can include, for example, compiled languages,interpreted languages, declarative languages, or procedural languages.Programs can be deployed in any form, including as stand-alone programs,modules, components, subroutines, or units for use in a computingenvironment. A computer program can, but need not, correspond to a filein a file system. A program can be stored in a portion of a file thatholds other programs or data, for example, one or more scripts stored ina markup language document, in a single file dedicated to the program inquestion, or in multiple coordinated files storing one or more modules,sub-programs, or portions of code. A computer program can be deployedfor execution on one computer or on multiple computers that are located,for example, at one site or distributed across multiple sites that areinterconnected by a communication network. While portions of theprograms illustrated in the various figures may be shown as individualmodules that implement the various features and functionality throughvarious objects, methods, or processes, the programs can instead includea number of sub-modules, third-party services, components, andlibraries. Conversely, the features and functionality of variouscomponents can be combined into single components as appropriate.Thresholds used to make computational determinations can be statically,dynamically, or both statically and dynamically determined.

The methods, processes, or logic flows described in this specificationcan be performed by one or more programmable computers executing one ormore computer programs to perform functions by operating on input dataand generating output. The methods, processes, or logic flows can alsobe performed by, and apparatus can also be implemented as, specialpurpose logic circuitry, for example, a CPU, an FPGA, or an ASIC.

Computers suitable for the execution of a computer program can be basedon one or more of general and special purpose microprocessors and otherkinds of CPUs. The elements of a computer are a CPU for performing orexecuting instructions and one or more memory devices for storinginstructions and data. Generally, a CPU can receive instructions anddata from (and write data to) a memory. A computer can also include, orbe operatively coupled to, one or more mass storage devices for storingdata. In some implementations, a computer can receive data from, andtransfer data to, the mass storage devices including, for example,magnetic, magneto-optical disks, or optical disks. Moreover, a computercan be embedded in another device, for example, a mobile telephone, apersonal digital assistant (PDA), a mobile audio or video player, a gameconsole, a global positioning system (GPS) receiver, or a portablestorage device such as a universal serial bus (USB) flash drive.

Computer-readable media (transitory or non-transitory, as appropriate)suitable for storing computer program instructions and data can includeall forms of permanent/non-permanent and volatile/non-volatile memory,media, and memory devices. Computer-readable media can include, forexample, semiconductor memory devices such as random access memory(RAM), read-only memory (ROM), phase change memory (PRAM), static randomaccess memory (SRAM), dynamic random access memory (DRAM), erasableprogrammable read-only memory (EPROM), electrically erasableprogrammable read-only memory (EEPROM), and flash memory devices.Computer-readable media can also include, for example, magnetic devicessuch as tape, cartridges, cassettes, and internal/removable disks.Computer-readable media can also include magneto-optical disks andoptical memory devices and technologies including, for example, digitalvideo disc (DVD), CD-ROM, DVD+/-R, DVD-RAM, DVD-ROM, HD-DVD, and BLURAY.The memory can store various objects or data, including caches, classes,frameworks, applications, modules, backup data, jobs, web pages, webpage templates, data structures, database tables, repositories, anddynamic information. Types of objects and data stored in memory caninclude parameters, variables, algorithms, instructions, rules,constraints, and references. Additionally, the memory can include logs,policies, security or access data, and reporting files. The processorand the memory can be supplemented by, or incorporated in, specialpurpose logic circuitry.

Implementations of the subject matter described in the presentdisclosure can be implemented on a computer having a display device forproviding interaction with a user, including displaying information to(and receiving input from) the user. Types of display devices caninclude, for example, a cathode ray tube (CRT), a liquid crystal display(LCD), a light-emitting diode (LED), and a plasma monitor. Displaydevices can include a keyboard and pointing devices including, forexample, a mouse, a trackball, or a trackpad. User input can also beprovided to the computer through the use of a touchscreen, such as atablet computer surface with pressure sensitivity or a multi-touchscreen using capacitive or electric sensing. Other kinds of devices canbe used to provide for interaction with a user, including to receiveuser feedback including, for example, sensory feedback including visualfeedback, auditory feedback, or tactile feedback. Input from the usercan be received in the form of acoustic, speech, or tactile input. Inaddition, a computer can interact with a user by sending documents to,and receiving documents from, a device that is used by the user. Forexample, the computer can send web pages to a web browser on a user'sclient device in response to requests received from the web browser.

The term “graphical user interface,” or “GUI,” can be used in thesingular or the plural to describe one or more graphical user interfacesand each of the displays of a particular graphical user interface.Therefore, a GUI can represent any graphical user interface, including,but not limited to, a web browser, a touch screen, or a command lineinterface (CLI) that processes information and efficiently presents theinformation results to the user. In general, a GUI can include aplurality of user interface (UI) elements, some or all associated with aweb browser, such as interactive fields, pull-down lists, and buttons.These and other UI elements can be related to or represent the functionsof the web browser.

Implementations of the subject matter described in this specificationcan be implemented in a computing system that includes a back-endcomponent, for example, as a data server, or that includes a middlewarecomponent, for example, an application server. Moreover, the computingsystem can include a front-end component, for example, a client computerhaving one or both of a graphical user interface or a Web browserthrough which a user can interact with the computer. The components ofthe system can be interconnected by any form or medium of wireline orwireless digital data communication (or a combination of datacommunication) in a communication network. Examples of communicationnetworks include a local area network (LAN), a radio access network(RAN), a metropolitan area network (MAN), a wide area network (WAN),Worldwide Interoperability for Microwave Access (WIMAX), a wirelesslocal area network (WLAN) (for example, using 802.11 a/b/g/n or 802.20or a combination of protocols), all or a portion of the Internet, or anyother communication system or systems at one or more locations (or acombination of communication networks). The network can communicatewith, for example, Internet Protocol (IP) packets, frame relay frames,asynchronous transfer mode (ATM) cells, voice, video, data, or acombination of communication types between network addresses.

The computing system can include clients and servers. A client andserver can generally be remote from each other and can typicallyinteract through a communication network. The relationship of client andserver can arise by virtue of computer programs running on therespective computers and having a client-server relationship.

Cluster file systems can be any file system type accessible frommultiple servers for read and update. Locking or consistency trackingmay not be necessary since the locking of exchange file system can bedone at application layer. Furthermore, Unicode data files can bedifferent from non-Unicode data files.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of what may beclaimed, but rather as descriptions of features that may be specific toparticular implementations. Certain features that are described in thisspecification in the context of separate implementations can also beimplemented, in combination, in a single implementation. Conversely,various features that are described in the context of a singleimplementation can also be implemented in multiple implementations,separately, or in any suitable sub-combination. Moreover, althoughpreviously described features may be described as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can, in some cases, be excised from thecombination, and the claimed combination may be directed to asub-combination or variation of a sub-combination.

Particular implementations of the subject matter have been described.Other implementations, alterations, and permutations of the describedimplementations are within the scope of the following claims as will beapparent to those skilled in the art. While operations are depicted inthe drawings or claims in a particular order, this should not beunderstood as requiring that such operations be performed in theparticular order shown or in sequential order, or that all illustratedoperations be performed (some operations may be considered optional), toachieve desirable results. In certain circumstances, multitasking orparallel processing (or a combination of multitasking and parallelprocessing) may be advantageous and performed as deemed appropriate.

Moreover, the separation or integration of various system modules andcomponents in the previously described implementations should not beunderstood as requiring such separation or integration in allimplementations, and it should be understood that the described programcomponents and systems can generally be integrated together in a singlesoftware product or packaged into multiple software products.

Accordingly, the previously described example implementations do notdefine or constrain the present disclosure. Other changes,substitutions, and alterations are also possible without departing fromthe spirit and scope of the present disclosure.

Furthermore, any claimed implementation is considered to be applicableto at least a computer-implemented method; a non-transitory,computer-readable medium storing computer-readable instructions toperform the computer-implemented method; and a computer systemcomprising a computer memory interoperably coupled with a hardwareprocessor configured to perform the computer-implemented method or theinstructions stored on the non-transitory, computer-readable medium.

What is claimed is:
 1. A computer-implemented method comprising:determining, in real-time, values of drilling parameters of a drillingsystem drilling a wellbore, wherein the drilling parameters comprise: arate of penetration (ROP) of a drilling tool of the drilling system infeet/hour, a hole size of the wellbore in feet, and a flow rate (GPM) ofthe drilling fluid at a mud pump of the drilling system in gallon perminutes; calculating, based on the values of the drilling parameters, acuttings concentration in an annulus of the wellbore (CCA), wherein theCCA is calculated using the equation:${{CCA} = \frac{{ROP}*{hole}{size}^{2}}{1471*{GPM}*TR}},$ and wherein TRis a dimensionless cuttings transport ratio; calculating, based on thecalculated CCA and a mud weight (MW) of a drilling fluid, an effectivemud weight (MW_(eff)) of the drilling fluid; and controlling, based onthe effective mud weight, a component of the drilling system to adjustat least one of the drilling parameters.
 2. The computer-implementedmethod of claim 1, wherein the effective mud weight is calculated usingthe equation:(MW _(eff))=(MW*CCA)+MW.
 3. The computer-implemented method of claim 1,wherein controlling, based on the effective mud weight, a component ofthe drilling system to adjust at least one of the drilling parameterscomprises: determining, based on the effective mud weight, a rate ofpenetration for a drilling tool of the drilling system; and controllingthe drilling tool such that the rate of penetration of the drilling toolis less than or equal to the determined rate of penetration.
 4. Thecomputer-implemented method of claim 3, wherein determining the rate ofpenetration for the drilling tool is further based on a pore pressurelimit and a fracture pressure limit.
 5. The computer-implemented methodof claim 3, wherein the rate of penetration is calculated using theequation:${{ROP} = \frac{810*\left( {{MW}_{eff} - {MW}} \right)*GPM}{\left( {{MW}*{OH}^{2}} \right)}},$where OH is an open hole size of the wellbore.
 6. A non-transitory,computer-readable medium storing one or more instructions executable bya computer system to perform operations comprising: determining, inreal-time, values of drilling parameters of a drilling system drilling awellbore, wherein the drilling parameters comprise: a rate ofpenetration (ROP) of a drilling tool of the drilling system infeet/hour, a hole size of the wellbore in feet, and a flow rate (GPM) ofthe drilling fluid at a mud pump of the drilling system in gallon perminutes; calculating, based on the values of the drilling parameters, acuttings concentration in an annulus of the wellbore (CCA), wherein theCCA is calculated using the equation:${{CCA} = \frac{{ROP}*{hole}{size}^{2}}{1471*{GPM}*TR}},$ and wherein TRis a dimensionless cuttings transport ratio; calculating, based on thecalculated CCA and a mud weight (MW) of a drilling fluid, an effectivemud weight (MW_(eff)) of the drilling fluid; and controlling, based onthe effective mud weight, a component of the drilling system to adjustat least one of the drilling parameters.
 7. The non-transitory,computer-readable medium of claim 6, wherein the effective mud weight iscalculated using the equation:(MW _(eff))=(MW*CCA)+MW.
 8. The non-transitory, computer-readable mediumof claim 6, wherein controlling, based on the effective mud weight, acomponent of the drilling system to adjust at least one of the drillingparameters comprises: determining, based on the effective mud weight, arate of penetration for a drilling tool of the drilling system; andcontrolling the drilling tool such that the rate of penetration of thedrilling tool is less than or equal to the determined rate ofpenetration.
 9. The non-transitory, computer-readable medium of claim 8,wherein determining the rate of penetration for the drilling tool isfurther based on a pore pressure limit and a fracture pressure limit.10. The non-transitory, computer-readable medium of claim 8, wherein therate of penetration is calculated using the equation:${{ROP} = \frac{810*\left( {{MW}_{eff} - {MW}} \right)*GPM}{\left( {{MW}*{OH}^{2}} \right)}},$where OH is an open hole size of the wellbore.
 11. Acomputer-implemented system, comprising: one or more processors; and anon-transitory computer-readable storage medium coupled to the one ormore processors and storing programming instructions for execution bythe one or more processors, the programming instructions instructing theone or more processors to perform operations comprising: determining, inreal-time, values of drilling parameters of a drilling system drilling awellbore, wherein the drilling parameters comprise: a rate ofpenetration (ROP) of a drilling tool of the drilling system infeet/hour, a hole size of the wellbore in feet, and a flow rate (GPM) ofthe drilling fluid at a mud pump of the drilling system in gallon perminutes; calculating, based on the values of the drilling parameters, acuttings concentration in an annulus of the wellbore (CCA), wherein theCCA is calculated using the equation:${{CCA} = \frac{{ROP}*{hole}{size}^{2}}{1471*{GPM}*TR}},$ and wherein TRis a dimensionless cuttings transport ratio; calculating, based on thecalculated CCA and a mud weight (MW) of a drilling fluid, an effectivemud weight (MW_(eff)) of the drilling fluid; and controlling, based onthe effective mud weight, a component of the drilling system to adjustat least one of the drilling parameters.
 12. The computer-implementedsystem of claim 11, wherein the effective mud weight is calculated usingthe equation:(MW _(eff))=(MW*CCA)+MW.
 13. The computer-implemented system of claim11, wherein controlling, based on the effective mud weight, a componentof the drilling system to adjust at least one of the drilling parameterscomprises: determining, based on the effective mud weight, a rate ofpenetration for a drilling tool of the drilling system; and controllingthe drilling tool such that the rate of penetration of the drilling toolis less than or equal to the determined rate of penetration.
 14. Thecomputer-implemented system of claim 13, wherein determining the rate ofpenetration for the drilling tool is further based on a pore pressurelimit and a fracture pressure limit.